1 /*-
2  * Copyright (c) 2018 Conrad Meyer <cem@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include "zstd_kfreebsd.h"
30 #include <sys/param.h>
31 #include <sys/endian.h>
32 
33 #ifndef _KERNEL
34 #include <strings.h>
35 #endif
36 
37 /*
38  * The kernel as a standalone target does not link against libgcc or
39  * libcompiler-rt. On platforms (e.g., MIPS and RISCV) that do not have a
40  * direct assembly implementation of the relevant builtin functions that zstd
41  * references, the compiler converts them into calls to the runtime library
42  * intrinsics.  Since the kernel does not link against the runtime libraries,
43  * this results in a failure to link the kernel.
44  *
45  * The goal of the following definitions is to use supported kernel constructs
46  * to implement the same functionality, without adding diff to the Zstd contrib
47  * code.
48  *
49  * A subsequent enhancement might create a mini compiler-rt library for kernel
50  * use and move these over there instead.
51  */
52 
53 /* Swap endianness */
54 int
55 __bswapsi2(int x)
56 {
57 	return (bswap32(x));
58 }
59 
60 long long
61 __bswapdi2(long long x)
62 {
63 	return (bswap64(x));
64 }
65 
66 /* Count trailing zeros */
67 int
68 __ctzsi2(int x)
69 {
70        if (x == 0)
71                return (sizeof(x) * NBBY);
72        return (ffs(x) - 1);
73 }
74 
75 long long
76 __ctzdi2(long long x)
77 {
78        if (x == 0)
79                return (sizeof(x) * NBBY);
80        return (ffsll(x) - 1);
81 }
82 
83 /* Count leading zeros */
84 int
85 __clzsi2(int x)
86 {
87        return (sizeof(x) * NBBY - fls(x));
88 }
89 
90 long long
91 __clzdi2(long long x)
92 {
93        return (sizeof(x) * NBBY - flsll(x));
94 }
95